The present invention relates to a semiconductor device, and more particularly, to a semiconductor device for improving a fuse cutting error.
Semiconductor devices like a memory device and a memory merged logic (MML) device include numerous memory cells for storing data. However, when any one of the memory cells fails, the semiconductor device also fails, so that the yield is decreased. It is not cost-effective to discard the whole device even when defects are generated only in a part of cells of the semiconductor device. Hence, in a semiconductor device, a repair function is required to increase the yield. A semiconductor device employs a method of replacing a defective cell with a redundant cell. A cuttable fuse is used to replace the defective cell with the redundant cell. Accordingly, a plurality of fuses is included in the semiconductor device, and these fuses can be cut by laser. The fuses are selectively cut according to a test result after the semiconductor device is tested.
The repairing method using the redundant cell previously sets a redundant word line provided to replace a normal word line and a redundant bit line provided to replace a normal bit line in a given cell array, and replaces the normal word line or the normal bit line which includes a failed cell with the redundant word line or the redundant bit line to repair the failed cell.
To this end, the memory device includes a circuit for replacing an address corresponding to the failed cell with an address of the redundant cell when the failed cell is chosen through the test after the wafer fabrication is completed. Accordingly, when an address signal corresponding to the failed cell is inputted, data of the replaced redundancy cell corresponding to the failed cell is accessed.
The most widely used method among repairing methods is a method of burning a fuse with a laser beam to perform blowing, so that a route of the address is replaced to select the redundant cell. Accordingly, the memory device includes a fuse unit which can change the address route by irradiating a laser to the fuse. In this description, a fuse refers to a wiring which is cut by the irradiation of a laser, and a fuse box refers to an area surrounding the fuse.